Many different types of transparencies are known in the art. They can be made by different printing and imaging methods, such as thermal transfer printing, ink-jet printing and plain paper copying, such as electrography and xerography. These transparencies are suitable for use with overhead projectors.
In the formation and development of xerographic images, a toner composition comprised of resin particles and pigment particles is generally applied to a latent image generated on a photoconductive element. Thereafter, the image is transferred to a suitable substrate, such as a transparent receiving sheet, and affixed there by the application of heat, pressure, or a combination thereof.
It is also known that transparencies can be selected as a receptor for thermal mass transferred images originating from thermal printing devices. Typically, these transparent sheets are comprised of thin films of one or more organic resins, such as polyesters, which have the disadvantage in that undesirable poor image adhesion results with such materials.
Although there are many recording sheets available for use, as known in the art, there remains a need for new recording sheets with coatings thereover that will enable the formation of images with high optical densities, good feedability, low haze and excellent toner or ink adhesion, especially for high speed copiers. In general, toner adhesion problems can be eliminated if one uses similar type of binder resin both for the toner and recording sheet coating, as discussed in EP 0349,227. However, that means the coating for the recording sheets would have to be changed every time a different toner resin is used. Further, some of these toner resins might only be feasible in solvent-based coatings, as in EP 0 349 227.
For the water-based coatings, the backing is usually primed with corona treatment or a coating of polyvinylidene chloride to achieve good adhesion between receptive coating and backing. For all the coatings cited above, antistatic agents are also needed in the receptive coating layer to achieve antistatic properties needed.